This application claims the priority of European application 99120136.9, filed Oct. 8, 1999, the disclosure of which is incorporated herein by reference in its entirety.
The present invention relates to a device for controlling a physical system as to applications of such a device.
By xe2x80x9cphysical systemxe2x80x9d, we understand any system that can vary its state in time and the state of which is expressed by physical parameters, wherein the state of the system can be influenced by physical control signals. Examples for such systems are e.g. the traffic of vehicles and/or pedestrians, objects in a storage or in a distribution system, etc.
For controlling such systems, complex devices are required, such as traffic controls, warehouse management systems, etc. Due to their complexity, the design, installation and maintenance of such devices are complicated and costly.
Hence, it is a general object of the invention to provide a device of this type that is simpler to design, install and maintain.
Now, in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the device for controlling a physical system in an extended area is based on detecting parameters of said system and generating control signals for influencing said system and it comprises a plurality of substantially identical cell units arranged periodically over said area, wherein each cell comprises at least one detector for detecting at least one of said parameters, an output for generating at least one of said control signals, communication ports connected to neighboring cell units in said area, and a control controlling said output as a function of the at least one parameter detected by said detector and of information received through said communication ports.
In another aspect, the invention relates to a device for controlling a traffic flow, preferably a traffic flow of pedestrians, in an extended area and is based on detecting parameters of said traffic flow and generating control signals for influencing said traffic flow. It comprises a plurality of substantially identical cell units arranged periodically over said area, wherein each cell comprises at least one detector for detecting at least one of said parameters, an output for generating at least one of said control signals, communication ports connected to neighboring cell units in said area, and a control controlling said output as a function of the at least one parameter detected by said detector and of information received through said communication ports.
By using a plurality of identical cell units arranged periodically over the area to be controlled, the design, installation and maintenance of the device are simplified.
Preferably, the cell units form a regular, two dimensional pattern. Like tiles, they can be joined to form a substantially continuous floor of arbitrary shape, which again simplifies the design and installation of the device.
In a preferred embodiment, the cell units are substantially hexagonal and form a hexagonal pattern. It has been found that a hexagonal system provides better spatial resolution than e.g. an orthogonal one. Preferably, each cell unit comprises communication ports for communicating with each of its six neighbors, which results in a powerful communication pattern where each cell can send messages into six directions.
Besides hexagonal cell units, units of any other tessellatable shape are advantageous, or at least units having communication ports for communicating with as many neighbors as they have sides.
Communication between the cell units can be wireless, preferably by optical links. This obviates the need for providing physical connectors and therefore simplifies installation and increases reliability.
Preferably, each cell unit has power connectors connected to at least two, preferably all, neighboring cells, thereby forming a redundant power grid feeding all said cell units. Power supply to all cell units can be established by simply adjoining the cell units and linking their power connectors.
For starting up the system or individual cell units, each cell unit is provided with a bootstrapper, which load the parameters for controlling the behavior of the cells from its neighbors. These parameters can e.g. be numerical values, a program for a microprocessor, or a connection pattern for a programmable gate array.
Examples of physical systems that can be controlled by the present device are:
Moving objects (such as pedestrians or vehicles) in a given area, wherein the control signals are signs, lights, sounds etc. that can be perceived by the objects. Applications are e.g. traffic control systems for vehicles or pedestrians or a game arena where the players act according to rules determined by the signs, lights etc.
A flow pattern of a fluid, wherein the control signals are adjustable vanes guiding the flow.
Objects to be conveyed, wherein the control signals are actuators (such as conveyor units) moving the objects in various directions. Applications are e.g. automatic storage or distribution systems.